1. Field of the Invention
The present invention relates to a starter having a thermal insulation cover for thermal insulation from an engine or an exhaust pipe.
2. Background of the Invention
It is a recent tendency to install more auxiliary equipment than before in the engine compartment of an automotive vehicle. A starter has to be mounted in the engine compartment more closely to an engine block or to an engine exhaust pipe. The starter is therefore subjected to heat radiation from the engine and the exhaust pipe. As a result, resin-made parts (e.g., molded cover of a magnet switch), rubber-made parts and the like used in the starter are very likely to be damaged due to thermal softening or thermal degradation.
Japanese Utility Model Laid-open Publication No. 61-101457 proposes to surround at least a part of the starter outer periphery with a thermal insulation cover. The thermal insulation cover is fixed to the starter with its engagement portions formed in a semicylindrical or hook shape by punching being engaged with a through bolt which tightly holds an end frame and a housing. The heat-shielding cover thus engaged with the through bolt via the engagement portions will possibly produce chattering or backlash noise sounds due to vibration and cause cracks in the thermal insulation cover due to the vibration.
Further, brushes movably held in respective brush holders collide with the brush holders during sliding contact with a commutator, particularly when the engine vibration is transmitted. This will cause local wear of the brushes at the colliding parts, cracks in the brushes and the like.